Не могу придумать как перевести "Variable deposit" - изменяемое месторождение??? Речь идет о месторождении бора. Контекст ниже:

The deposit appears to be highly variable; datolite is insoluble and is relatively hard (although it does fracture easily); the overburden ratio is extremely high is certain areas; processing is complex; there is considerable pollution; and the location is far from ideal.